Studies on medium-chain fatty acyl-coenzyme a synthetase. Enzyme fraction II: mechanism of reaction and specific properties.
1. The mechanism of reaction of fatty acyl-CoA synthesis catalysed by fatty acyl-CoA synthetase from ox liver (fraction II; Bar-Tana, Rose & Shapiro, 1968) was investigated by a kinetic study of CoA disappearance dependent on butyrate plus ATP or butyryl-AMP (overall and partial reaction b respectively). 2. Contrary to findings with another enzyme (fraction I), a Bi Uni Uni Bi Ping Pong mechanism (Cleland, 1963a,b,c) corresponding to Berg's (1956) scheme of reaction was eliminated and an ordered Ter Ter mechanism with an A-C-B (standing for ATP, CoA and butyrate respectively) sequence of substrate entry for the overall reaction was established for fraction II. Partial reaction (b) was found to follow the ;Iso-Theorell-Chance' mechanism. 3. Also, in contrast with results obtained with fraction I, no allosteric properties could be demonstrated with fraction II.
D000227:Adenine Nucleotides / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002087:Butyrates / Q000378:metabolism*; D002417:Cattle; D003065:Coenzyme A / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008956:Models, Chemical
D000227:Adenine Nucleotides; D002087:Butyrates; D000255:Adenosine Triphosphate; D008025:Ligases; D003065:Coenzyme A